Certain radio frequency (RF) applications perform signal processing operations by separating radio frequency signals into signal components representing in-phase and quadrature channels (I and Q channels). Generally, such applications contain circuitry, such as a quadrature signal generator, for producing the in-phase and quadrature signal components with a phase separation of ninety degrees. One example of a prior art quadrature signal generator is described in U.S. Pat. No. 4,908,532 issued to Chadwick on Mar. 13, 1990. Here, a phase shifting network generates signals with a ninety degree phase difference. A phase detector supplements the phase shifting network by detecting deviations from the desired 90 degree separation, and by producing a control signal to restore and maintain the 90 degree phase difference.
The accuracy of quadrature signal generators depends on the design, and on the quality of the manufacturing process and of the components used in the attendant circuitry. Variances in the manufacturing process and in component quality may lead to degradation in circuit performance. For example, the effectiveness of the corrective action performed by the phase detector described in Chadwick depends on the ability of the phase detector to correctly determine phase deviations. The phase detector may suffer from imperfections in its circuitry and thus be unable to render proper phase detection for precise signal generation. Precise generation of in-phase and quadrature signal components is desirable in many applications. Thus, a solution needed that is less susceptible to manufacturing imperfections, and that is more likely to produce precise signals.